Vectronics VEC-1500K User Manual

Page 33

The objective is to solder the lead to the inside of the hole. Heat the lead and
plate-through eyelet for about 1 second. Then, apply solder to the surface--
allowing it to melt and wick down around the lead. Avoid loading up the pad
with solder--the important thing is to fill the gap around the lead. Nip off any
excess lead when the connection is complete.

Apply solder

to opposite side

Allow solder to wick

down into hole

around lead.

of lead.

Use a similar soldering technique when installing components in multilayer
boards. Note that plate-through vias do not require soldering because electrical
contact is already established between layers by the plate-through itself.

Hand Wiring Techniques

Before the days of PC boards, virtually all electronic interconnections were
made using wire. Today, designers try to include everything--jacks, switches,
connectors, and indicator lamps--on the printed circuit board. The reasoning is
simple! It's a lot cheaper and faster to install "user-interface" components on a
PC board with automated soldering than it is to hand-wire these parts onto a
control panel using wire! Despite this, we haven't entirely escaped the need for
hand wiring. When interconnections are made using wire, it's called point-to-
point wiring.

Point-to-point wiring is still widely used to interconnect circuit

boards, power and signal leads, and electromechanical devices that can't be
included on PC boards.

Cable Terminations:

Interconnecting cables take two forms. Some may be

soldered directly to pads provided on the circuit board. Others may be soldered
to connectors that plug into the circuit board. Either way, interconnecting cables
must be prepared carefully because they'll be subject to flexing and movement.
Stranded wire is commonly used because it is more flexible than solid wire and
it's less likely to break. Harnessing wires together with plastic ties helps to
immobilize them, reducing stress. Good soldering technique reduces the chances
of breakage or short-circuiting on the circuit board (see following diagram).